Architectural Engineering

 

First Advisor

Lily M. Wang

Date of this Version

8-2017

Comments

A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science Major: Architectural Engineering Under the Supervision of Professor Lily M. Wang Lincoln, Nebraska August, 2017

Copyright (c) 2017 Sungbeen Cho

Abstract

The listener’s surrounding environment affects the perception of sound. The environment includes physical factors such as space size, shape, and finish materials, and psychological factors such as individual difference of impression, and vision. Acoustic spatial impression can be defined as the concept of the type and size of space at which a listener arrives spontaneously when he/she is exposed to an appropriate sound field. This thesis analyzes how physical factors in enclosed spaces affect the acoustic spatial impression, and how sound sources at different positions on stage are perceived in different shapes of spaces.

First, existing spatial impression parameters, IACC (Interaural Cross-Correlation Coefficient) and LF (Lateral Energy Fraction), are analyzed to see how they vary across different source positions. In addition, how acoustic energy changes according to the sound source location is measured and observed in actual spaces, and a new metric named ILD-Correlation Range (ILD-CR) is suggested to understand spatial impression across varying source positions. This metric is based on the Interaural Level Difference (ILD), an important factor in localization perception.

Next, the thesis explores how the shape of the space and the positions of the sound source on stage influence human perception through subjective testing using auralizations, across rooms with different reverberation times and at two distances between sound source and listener. The ILD is found to vary according to the shape of the space, and localization perception demonstrates significant similarity to the ILD. Other factors besides the shape of the room, such as reverberation time, the distance between sound source and listener, and frequencies are also found to have a significant effect on the listener’s spatial perception.

Advisor: Lily M. Wang

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